Oum Er-Rbia (Arabic: أم الربيع, romanized: the mother of spring) is a large, long and high-throughput river in central Morocco.
The river is 555 kilometres (345 mi) long. With an average water throughput of 105 m/s, Oum Er-Rbia is the second-largest river in Morocco after the Sebou River. It originates in the Middle Atlas and passes through the city of Khénifra, arriving at its mouth at the Atlantic Ocean at the port of Azemmour, located on its left bank. Oum Er-Rbia has six dams, the most important of which is Al Massira Dam. Its most important tributaries are the El-Abid River, the Tessaoute River, and the Lakhdar River.